“Surface Leakage Protection Device” (SLPD) which is based on electric leakage protection, compared with “Residual Current Device” (RCD) which is based on the residual current monitoring, can cut off the electrical connection between an electric device and the power source before a person touches the energized surface of the electric device due to electric leakage, turning passive “electric shock protection” into active “electric leakage prevention”. Patent document 201120482689.8 “The surface leakage detection and prevention method and system” gives the solution of leakage detection of a specific “surface leakage protection device”. A SLPD monitors the electric potential difference between the neutral wire of the power source and surface of the electric device, once the potential difference exceeds a preset threshold, drives follow-up circuit to break the main circuit switch, thereby breaking the connection between the electric device and the power source.